Data center networks have become massively large in order to meet data processing demands. This enlargement raises various scaling challenges in terms of forwarding table size for each node in a network, control plane information flooding, network convergence, etc. Various proposals are underway for addressing the above challenges. For example, Intermediate System (ISIS) Spine Leafe (ISIS-SL) (Spine-Leaf), Routing in Fat Trees (RIFT), etc. are few of the proposals to address the challenges in data center routing.
One specific challenge in data center routing is the problem of link failures between two nodes within a network fabric and/or failure of intermediate/spine nodes (e.g., nodes of the fabric other than leaf nodes). Such failures can result in black holes. Black holes occur when traffic destined to or originating from a particular network prefix, via the failed link and/or a failed intermediate node, arrives and remain at the failed intermediate node without being delivered to its intended destination due to the failure. Prefix disaggregation is a mechanism by which, after a failure is detected, either an intermediate node creates and advertises a traffic routing policy to downstream nodes not to use the intermediate node for one or more affected network prefixes or other functioning intermediate nodes create and advertise traffic routing policies to downstream nodes to use one or more of the functioning intermediate nodes to reach the affected network prefixes.
These prefix disaggregation mechanisms and policies are created an implemented in a reactive manner (in response to a detected link/node failure) and thus are inefficient and introduce unnecessary delays in fixing or adjusting traffic routing to avoid failures.